|California Pumped Power and Harvey's Bomb|
Oroville Dam is at the upper left, Helm's Creek Pumped Power Plant is at the lower right.
As you can see from the map the Oroville site is much closer than the Helms Creek site, so why did John Birges go to Helms Creek to steal his dynamite instead of Oroville? Probably because construction had finished at Oroville ten years earlier but was ongoing at Helms Creek. It would have been more likely to find dynamite at an ongoing construction site.